Abstract
The amplitude distribution of miniature postsynaptic currents (minis) in many central neurons has a large variance and positive skew, but the sources of this variance and skew are unresolved. Recently it has been proposed that spontaneous Ca2+ influx into a presynaptic bouton with multiple release sites could cause spontaneous multiquantal minis by synchronizing release at all sites in the bouton, accounting for both the large variance and skew of the mini distribution. We tested this hypothesis by evoking minis with internally perfused, buffered Ca2+ and the secretagogue α-latrotoxin, both in the absence of external Ca2+. With these manipulations, the synchronized release model predicts that the mini distribution should collapse to a Gaussian distribution with a reduced coefficient of variation. Contrary to this expectation, we find that mini amplitude distributions under these conditions retain a large variance and positive skew and are indistinguishable from amplitude distributions of depolarization-evoked minis, strongly suggesting that minis are uniquantal.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1293-1304 |
| Number of pages | 12 |
| Journal | Journal of Neurophysiology |
| Volume | 78 |
| Issue number | 3 |
| State | Published - Sep 1997 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Physiology
- Neuroscience(all)
Cite this
Are some minis multiquantal? / Frerking, Matthew; Borges, Salvador; Wilson, Martin.
In: Journal of Neurophysiology, Vol. 78, No. 3, 09.1997, p. 1293-1304.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Are some minis multiquantal?
AU - Frerking, Matthew
AU - Borges, Salvador
AU - Wilson, Martin
PY - 1997/9
Y1 - 1997/9
N2 - The amplitude distribution of miniature postsynaptic currents (minis) in many central neurons has a large variance and positive skew, but the sources of this variance and skew are unresolved. Recently it has been proposed that spontaneous Ca2+ influx into a presynaptic bouton with multiple release sites could cause spontaneous multiquantal minis by synchronizing release at all sites in the bouton, accounting for both the large variance and skew of the mini distribution. We tested this hypothesis by evoking minis with internally perfused, buffered Ca2+ and the secretagogue α-latrotoxin, both in the absence of external Ca2+. With these manipulations, the synchronized release model predicts that the mini distribution should collapse to a Gaussian distribution with a reduced coefficient of variation. Contrary to this expectation, we find that mini amplitude distributions under these conditions retain a large variance and positive skew and are indistinguishable from amplitude distributions of depolarization-evoked minis, strongly suggesting that minis are uniquantal.
AB - The amplitude distribution of miniature postsynaptic currents (minis) in many central neurons has a large variance and positive skew, but the sources of this variance and skew are unresolved. Recently it has been proposed that spontaneous Ca2+ influx into a presynaptic bouton with multiple release sites could cause spontaneous multiquantal minis by synchronizing release at all sites in the bouton, accounting for both the large variance and skew of the mini distribution. We tested this hypothesis by evoking minis with internally perfused, buffered Ca2+ and the secretagogue α-latrotoxin, both in the absence of external Ca2+. With these manipulations, the synchronized release model predicts that the mini distribution should collapse to a Gaussian distribution with a reduced coefficient of variation. Contrary to this expectation, we find that mini amplitude distributions under these conditions retain a large variance and positive skew and are indistinguishable from amplitude distributions of depolarization-evoked minis, strongly suggesting that minis are uniquantal.
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UR - http://www.scopus.com/inward/citedby.url?scp=0030756584&partnerID=8YFLogxK
M3 - Article
C2 - 9310421
AN - SCOPUS:0030756584
VL - 78
SP - 1293
EP - 1304
JO - Journal of Neurophysiology
JF - Journal of Neurophysiology
SN - 0022-3077
IS - 3
ER -